Pumps that are capable of maintaining a constant horsepower output, even as the pressure at which they operate fluctuates, are currently available. These pumps are designed to use a given amount of horsepower inputted into them, generally through a motor, and to maximize the amount of horsepower that they output, regardless of the pressure at which they operate. Thus, such pumps operate at higher performance levels than other pumps that are not capable of maintaining a constant horsepower output.
Typically, pumps that are capable of maintaining a constant horsepower output are operable in relatively low pressure ranges and are of complex axial design. On the other hand, pumps that are operable in higher pressure ranges are unable to maintain a constant horsepower output as the operating pressure of the pump changes. Typically, such higher pressure pumps are multi-stage pumps and are essentially made up of multiple pumps that are linked together using a mechanism for switching between the multiple pumps.
Accordingly, it would be desirable to provide novel pumps and methods that are capable of maintaining a constant horsepower output even at high pressures. It would also be desirable to provide novel pumps that consist of infinite stages (i.e., that are truly single pumps).
In addition to the above, it would also be desirable to provide pumps that are modular, and therefore easily and cost-effectively repairable. Further, it would be desirable to provide pumps that maximize efficiency by minimizing the total volume of the piston chambers included therein.